U.S. Pat. No. 3,581,733 describes a system for continuously bleeding a parenteral liquid, such as normal saline, into a patient during continuous monitoring of blood pressure. This continuous flow at a very slow rate into the patient prevents blood from entering the pressure measuring tubing where blood clots could give an erroneous reading. Periodically it becomes necessary to flush the system at a much faster rate to insure that no blood has started to coagulate around an arterial needle or catheter. Such flushing is accomplished in this patent by turning stopcock 18 so fluid flows through the flushing channel 14 rather than the restricted channel 16. Holding the stopcock in one hand and twisting the handle with another hand would be a tedious procedure, particularly when the flushing procedure had to be frequently used.
U.S. Pat. No. 3,675,891 describes a different type flushing valve in which an elongated stem is stretchingly pulled to open a valve. Enclosed is an instruction sheet for using this valve. Such stem pulling procedure has a disadvantage in that the procedure requires one hand to hold the valve and another hand to pull the stem if the valve is not firmly anchored to a supporting pole. Even if attached to a pole, a vigorous pulling of the stem could upset the whole structure.